Unable to get the scroll bar position of mdiclient

I created a mdi form and added mdi childs to it. when i move the mdi children outside the bounds of the form, scroll bars appear. I want to set a logo as the background of the mdi parent. So, when scroll bar position is changed, the background image must be redrawn with respect to the position of the scroll bars. I couldn't find any property that gives me the scroll bar position the mdi parent. Can anyone tell me how to get the scroll bar offset of mdiclient?

Note: I am using Visual Studio 2008, .Net3.5